Concussion affects how we process images that are close together, study shows

The way in which people process visual information is changed when suffering from concussion, research says. 

A new study from Manchester Metropolitan University Institute of Sport has found that concussion reduces a person’s ability to automatically group objects that are close together. 

The human brain relies on a set of perceptual grouping principles to organise and make sense of what a person sees.  

One of the most fundamental parts of these principles is grouping by proximity – when objects that are close to each other are perceived as a group or a unit.   

For example, words on a page without any context will appear to people with concussion as a random set of letters, rather than a complete story or passage. 

The findings will feed in to the understanding of how to manage and rehabilitate concussion, which has become a hot topic particularly in high-impact contact sports such as rugby.  

Researchers from the University of Waikato in New Zealand and Manchester Metropolitan University have shown that concussion reduces people’s ability to automatically group objects due to its effect on how the brain processes the individual features of a complete image. 

The study, published in Scientific Reports, used two visual illusions to demonstrate that people with a history of concussion may show deficits in grouping by proximity.  

Notably, researchers found that individuals with concussion struggled in the perception of both illusions compared to individuals without concussion.  

Dr Liis Uiga, Senior Lecturer at Manchester Metropolitan University Institute of Sport, said: “This important study shows that mild traumatic brain injury can directly affect the way people perceive objects by disrupting brain’s ability to group visual stimuli that are close together.  

“Consequently, individuals with a concussion may focus on individual details of an object rather than recognising patterns or structures.”  

Every year, concussion affects 42 million people worldwide. It is well-known that this causes a variety of visual impairments such as blurred vision, but little attention has been given to the perception of things that a person sees or how the brain brings visual information together. 

Amanpreet Sidhu, from the University of Waikato in New Zealand, said: “This research contributes to our understanding of the wide-ranging impacts of concussion and underscores the importance of considering visual perception in concussion management and rehabilitation protocols.  

“Further research in this area could yield additional insights into the specific mechanisms underlying visual impairments associated with concussion, paving the way more targeted interventions and improved outcomes for affected individuals.”